Mercury switch



Feb. 7, 1928.

\ 1,658,620 w. R. WALKER MERCURY SWITCH Filed May 26, 19

Patented Feb. 7, i928.

WARREN R. 'tVALIECEB, 0F GREJME. KILLS, NEW YURK, ASSIGNOR T0 COOPER HEWITT ELECTRIC QGMPAN'Y, 0F HOBQKEN, NEW JERSEY, A UORPQRATION OF NEW JERSEY.

MERCURY SWITGH.

Application filed May 26,1925. Serial No. 32,970.

My present invention relates to electric switches of theliquid tlow type and particularly to mercury switches. It further relates to switches of thistype having a sealed envelope-through which are sealed electrodes between which current path is .made and broken by the movement of the mercury with relation to the other parts of the switch, and in which a perforated part or septum is positioned across the envelope between the electrodes therein which is utilized for separating the mercury in the switch into two bodies in the open circuit position thereof and which permits the joining of the said two bodies oi mercury through the perforation thereof in the closed position of the switch, such septum being positioned close' to the wall ot the envelope throughout their adjacent portions but not sealed thereto, advantage being taken of the surface tension of the mercury to keep the mercury from flowing through the very small space between the septum and the envelope whereby is'per'mitted the construction of a switch which is cheaply made. The invention further relates to a switch of this type in which the envelope is made of glass and the septum oi the same or'another vitreous material whereby, due to these parts being made separate,

there is avoided the difiiculties in forming the septum and the envelope unitary which result in the crackingof the switch due to unavoidable strains. The invention further relates to-a switch of this type having an envelope of comparatively cheap glass and a septum which is separate therefrom and w ich is made of a material which is highly resistant to electric arcing.

I have discovered that a switch of this type which is adapted for making and breaking circuit therethrough either by ro-' tation of the switch or'b tilting of the switch lonits axi that a vantage can be I taken of the natural surface tension eflects of the mercury to prevent it from passing through very small passages so that a septum can be positioned in a switchbut made separate therefrom due allowances being made for'slight variations in size and manufacture and allowances also for changes in temperature and varying. changes in temperature in the difierent parts due to different co efilcients of linear expansion 'in' the materials thereof.

In the drawings, Fig. 1 is'a longitudinal sectional view of an embodiment of the switch of my invention showing a sealed envelope having mercury therein and electrodes sealed thereinto' from either end each of which has a downward extension for contact with the mercury and one of which has a further inward longitudinal extension which carries a septum extending across said envelope and in close proximity thereto throughout the circumference thereof, said septum being provided with an aperture through which in closed circuit posit-ions of the switch the mercury extends for making contact between said electrodes,-

Fig. 2 is a transverse sectional view of the device of Fig. 1 taken along the line 2-2 and looking in the direction of-the arrows in that figure,

Fig. 3 is a lon'gitudin'al'sectional view of an'alternative embodiment of my invention showing electrode extensions which extend around the interior of the envelope, and showing the switch in the open circuitposition, 5

Fig. 1 is a sectional view of the-device of Fig. 3 taken along line 4-4 and lookingin the direction of the arrows,

. Fig. 5 is a face view of an alternative form of septum "having two perforations "therethrough diametrically spaced,

Fig. '6 shows an alternative embodiment of the septum having one perforation which is extended arcuately "for permitting the closing of the circuit'during the predetermined 'peripd of time while the switch .is rotat-mg on its axis at a predetermined rate of speedand likewise be made to have the circuit 0 en therethrough for 9. correspond- "similar result is produced as with the septum of Fig. 6 but in which the open circuit periods are shorter withrespect to the closedcircuit periods and Fig. 9 shows aseptum having an annular groove cut in the edge thereof and material wound therein such as asbestos for sealing the space between the septum and the envelope wall when such an arrangement is necessary. I y

In Figs. 1 and 2 of the drawing the envelope 1 preferably of borosilicate glass such as G.,O,P glass carries sealed therethrough on each end electrode leads 2 and 3 which. extend inwardly toward each other and are axially aligned. Each of the'leads 2 and 3 carries an electrode 5 connected thereto which extends toward the envelope wall which. contact with the body of mer-.

- cury (l in the envelope, said lead 3 carries I advantage being taken of the natural surface tension of the mercury toprevent this flowing between the septum and the envelope whereby a space between septum and the envelope may be left to allow for expansion and contraction due to changes in temperature and to allow a certain degree of variation in the manufacture of the parts. :Between its oint of support and its edge said septum 7 as formed therethrough a perforation 8 for the flow of mercury therethrough to connect in the closed circuit 0- sition of the switch two pools into which the mercury is formed on either side of the se tum 7.

n the operation of this embodiment of my invention the switch is rotated on its axis to bring said perforation 8 below or above the level of the mercury 6 for mak-.

ing and breaking of a current path therethrough. In its operation as a simple switch it can be rotated" backward and forward to a small part to bring said opening -8 below or above the surface of the mercury as desired.- In operating the device as a time switch it is rotated continuously at a predetermined rate of speed whereby the septum in travelling from Its point of emerging from the mercury to its points of immersion therein occupies the predetermined period of time and likewise the movement of the opening from this point of immersion into its point of emerging from the mercury occupies the corresponding period of time, the time periods of the maklng and breaking of the circuit being recorded by the speedof rotation of the device. For

obtaining the making of a circuit through the device at shorter intervals than that possible with the device of Fig. 1 with reeat to the time periods of the opening of a e circuit a septum such as shown in Fig.

material such as fused quartz glass or septum and center of rotation whereby different periods of make and break maybe obtained as desired. In Fig. 6, for example, is shown the single erforation formed in the shape of an arc w ereby at a given rate of speed of rotation the period of circuitmake is lengthened and the eriod of circuit break is shortened. In Fig. 7 is shown a septum having a small perforation 9 at one point and a larger and arcuate perforation 10 at another portion whereby is obtained through the rotation of the switch intermittent periods of circuit make which are unequal in duration. And in Fig. 8 is showntwo equally spaced arcuate perforations 10 in the se tum 7. I

The device of igs. 1 and 2 may also be operated by tilting in which operation the perforation S is left in its position shown in 1 and 2 or brought to a point at a lesser depth inthe mercury as desired according to the current broken and as to whether a time interval is to be injected into 0 eration of the switch.

In igs. 3 and 4is shown in an open circuit position a switch similar to that of Figs. 1 and 2 with exception that electrodes 5, 5 mounted on electrode leads 2 and 3.

trodes in the mercury is precluded.

' The operation of the switch of Figs. 3 and 4 is substantially the same as that of the switch in Figs. 1 and 2 and is adapted for using the'septums of various sorts as has been described for the purpose of opening the intermittent makes and breaks of varying periods of time and varying alternations.

It is to be noted that in the device of my invention as has been described there is provided the switch simple of structure and mode of manufacture which can be operated without any appreciable change of center of gravity whatever, the only change being when the mercury extends through perforials than those above mentioned may be employed for the septum such. as oxidized aluminum whichhas the property of being an insulator and at the same time has the envelope and separate therefrom" between said electrodes, saidseptum being spaced away from but close enough to the envelope throughout adjacent portions to prevent the mercury from flowing therebetween, said septum being formed with an opening there through for connecting the said electrodes by mercury extending therethrough in a closed position of the switch.

2. In a liquid flow switch, a sealed envelope of glass, electrodes sealed through the wall of said envelope, mercury in said envelope, and an arc resisting septum positioned across the envelope and separate therefrom between said electrodes, said septum being spaced away from but close enough to the envelope throughout their adjacent portions to prevent the mercury from flowing therebetween, said septum being'itormed with an opening therethrough for connecting thesaid electrodes by mercury extending therev through in a closed position of the switch.

3. in a liquid flow switch, a sealed envelope, electrodes sealed throu h the wall of said envelope, mercury in said envelope, and an arc resisting septum positioned across the envelope and separate therefrom between said electrodes, said septum being spaced away from but close enough to the envelope throughout their adjacent portions to prevent the mercury from flowing therebetween yet having such a distance between them as to preclude excessive strains therebetween due to any contact through change of dimension resulting from changes of temperature normal to manufacturing and operating conditions of the switch, said se tum being formed with an opening theret rough for connecting the said;'electrodes by mercury extending'therethrough in a closed position of the switch. I

4. in a liquid flow switch, a sealed envelope, electrodes sealed throu h the wall of said envelope, mercury in sai envelope, and

a septum of fused quartz positioned across the envelope and separate therefrom between said electrodes and positioned close enough to the envelope throughout their adjacent portions to prevent the mercury from flowing therebet'ween yet having such a distance between them as to preclude excessive strains therebetween due to any contact through change of dimension resulting from changes of temperature normal to operating condi-- tions of the switch, said septum being formed with an opening therethrough for connecting the said electrodes by mercury extending therethrough in a closed position of the switch.

5. In a liquid flow switch, a sealed envelope qof boro-silicate glass, electrodes sealed through the wall of said envelope, mercury in said envelope and separate therefrom, and an arc resisting septum positionedacross the envelope between said electrodes, said septum being spaced away from but close enough to such envelope throughout their adjacent portions to prevent the mercury from flowing therebetween, said septum be ing formed with an opening therethrough for connecting the said electrode by mercury extending therethrough in a'closed position of the switch.

6. In a liquid'flow switch, a sealed envelope of boro-silicate glass, electrodes sealed through the wall of said envelope, mercury inysaid envelope, and an arc resisting septum of vitreous material positioned across the envelope and separate therefrom between said electrodes, said septum being spaced away from but close enough to such envelope throughout their adjacent portions to prevent the mercury from flowing therebetween yet havin such a distance between them as to preclu e excessive strains therebetween due to any contact through change of dimension resulting from changes of temperature normal to operating conditions of the switch, said-septum being formed with an opening therethrough'for connecting the said electrodes by mercury extending therethrough in a closed position of the switch.

7. In a liquid flow switch, a sealed envelope of bore-silicate glass, a 'pair of electrodes sealed through the wall of said envelope one at each end thereof and axially aligned, mercury in said envelope, and a se turn of fused quartz positioned across t e envelope between said electrodes and positioned close enough to such envelope throughout their adjacent portions to prevent the mercury from flowing therebetween yet having' such a distance between them as to preclude excessive strains therebetween due to any contactthrough change of dimension envelope between the electrodes and having 9. In an electrlc tlIIlBSWltCll, a sealed envelope having electrodes sealed thereinto,

mercury therein, a septum extending across the envelope between the electrodes and having a plurality of openings therethrough for joiningthe' two spaces into which the septum-divides the envelope said openings being of unequal angular extension with respect to the axis of rotation of the switch.

10. In a liquid flow switch, a sealed envelope, electrodes sealed through the wall of said envelope, mercury in said envelope, and an arc resisting septum positioned across the envelope between said electrodes a groove about its edge with packing material therein to prevent the mercury "from flowing therebetween, said septum being formed with an opening therethrough for connecting the said electrodes by mercury extending there throu h in a closed osition of the switch;

11. a liquid ow switch, a sealed envelope, electrodes sealed through the wall of said envelope, mercury in said envelope, and

an arc resisting septum positioned across the envelo e between said electrodes and positioned c ose to such envelope and having packing material therebetween throughout their adjacent portionsto prevent the mercury from flowing therebctween, saidseptum being formed with an opening therethrough for connecting the said electrodes by mercury extending therethrough in a closed-position of the switch.

12. In a mercury switch in combination, a

sealed vitreous container, a septum therein and a support therefor comprising a wire fixed to said septum and fixed to said container, electrodes sealed into said container and a liquid therein.

13. In a mercury switch in combination, a sealed vitreous container, mercury therein, a septum therein dividing it into two chamhers, means for supporting said septumin position in said container, said septum bepermit expansion and contraction but small enough for thesurface tension of the mercury to hold the mercury against passage between said septum and the container, said switch having a passageway for the flow of mercury to and from one chamber of said envelope to'the other for making and brealc .ing current path through the switch.

14. In a mercury swlt-ch, in combination, asealed container, a septum of vitreous material there1n,.support for said septum comprisinw a wire fixed to said septum and fixed .ing separate from the container and spaced apart therefrom at a distance sufiicient to to sai container, electrodes sealed into said container, and a conducting liquid therein.

15. In a mercury switch, in combination,

a sealed container of hero silicate glass. :1. septum of fused silica therein, a support for said septum comprising a wire fixed to said septum and fixed to said container, electrodes scaled into said container, and a conducting liquid therein. c

- Signed at Hobbkem'in the county of Endson and State of New Jersey, this 21st day of May, A. D. 1925.

WARREN R. WALKER. 

